A sensor element is known, for example, from German Patent No. DE 100 35 036 or German Patent Application No. DE 101 00 599. The sensor element includes a first and a second solid electrolyte layer. A first printed conductor having a first electrode and a first feed line and a second printed conductor having a second electrode and a second feed line are provided on opposite sides of the first solid electrolyte layer. The first electrode is positioned on an outer surface of the sensor element and is in contact with the measuring gas via an open-pored protective layer. The second electrode is positioned in a measuring gas chamber introduced into the sensor element and is connected to the measuring gas via a diffusion resistor and via a gas access opening. A third printed conductor having a third electrode and a third feed line, which is attached to the first or the second solid electrolyte layer, is provided between the first and the second solid electrolyte layers. The third electrode is subjected to a reference gas and forms an electrochemical cell (Nernst cell) with an electrode (the second electrode or a fourth electrode, for example) positioned in the measuring gas chamber. The second feed line to the second electrode and the third feed line to the third electrode run next to one another in the direction of the longitudinal axis of the sensor element in one layer plane of the sensor element.
In a system of this type, it is disadvantageous that rapid oscillation of the potential at the first electrode caused by rapid changes in the oxygen partial pressure of an exhaust gas of an internal combustion engine, for example, may impair the signal of the Nernst cell. Since the pump voltage applied between the first and the second electrodes by an external circuit is regulated using the signal of the Nernst cell, and since the pump current flowing because of this pump voltage provides the measuring signal, influencing of the Nernst voltage may corrupt the measuring signal.